Electric Motor Vehicle Auxiliary Unit Circuit Board Fixation
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Solution Overview
Problem
Existing electric motor vehicle auxiliary units with electronically commutated canned motors face challenges in cost-effectively fixing the motor control with high operational reliability, particularly due to complex production processes and potential for leakage currents or short circuits from conductor track abrasion.
Innovation Solution
The motor vehicle auxiliary unit employs axial support knobs to space the circuit board body from the partition wall, using a single fastening element and coating-free zones at support points to prevent conductor track abrasion, combined with a thermally conductive compound for efficient heat dissipation, ensuring reliable fixation and cooling of power semiconductors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the circuit board body is directly attached to the partition wall, then the production process is simplified, but conductor track abrasion occurs leading to leakage currents or short circuits
Solution Approach 1:
The partition wall is segmented by adding axial support knobs that protrude from the partition wall surface. These knobs create discrete support points that elevate the circuit board body, preventing direct contact between the board and the partition wall. This segmentation approach maintains production simplicity while eliminating conductor track abrasion at contact points, thereby resolving the contradiction between ease of manufacture and operational reliability.
Solution Approach 2:
The axial support knobs act as intermediary elements between the partition wall and the circuit board body. Instead of direct contact, the knobs provide elevated support points that prevent the circuit board from rubbing against the partition wall during vehicle vibrations and shocks. This intermediary structure preserves manufacturing simplicity while ensuring long-term operational reliability by preventing conductor track damage.
2Reliability
If multiple fastening elements are used to secure the circuit board body, then fixation reliability is improved, but production complexity and cost increase
Solution Approach 1:
The fastening function and the spacing/support function are merged into a single integrated component: the axial support knob. These knobs both elevate the circuit board body to prevent abrasion and serve as attachment points for fastening elements. By combining multiple functions into one structure, the patent achieves reliable fixation without increasing production complexity or requiring multiple separate fastening components.
Solution Approach 2:
The axial support knobs perform multiple functions simultaneously: they provide spacing between the circuit board and partition wall, serve as mounting points for fastening elements, and create coating-free zones to prevent abrasion. This multi-functionality allows reliable fixation to be achieved with minimal components, reducing production complexity while maintaining high fixation reliability.
3Temperature
If the circuit board body is in direct contact with the partition wall, then heat dissipation is improved, but conductor track abrasion leads to short circuits
Solution Approach 1:
The support knobs extend in the axial dimension, creating elevation rather than relying solely on planar contact for heat dissipation. This dimensional approach allows the circuit board to be spaced from the partition wall while maintaining thermal connection through the knob structures, balancing heat dissipation needs with the prevention of conductor track abrasion.
4Reliability
If coating-free zones are provided at support points, then conductor track abrasion is prevented, but manufacturing precision requirements increase
Solution Approach 1:
The axial support knobs are pre-formed on the partition wall before circuit board assembly. These knobs create predetermined coating-free zones at their contact points with the circuit board. By establishing these zones in advance through the knob structure rather than requiring precise coating control, the patent reduces manufacturing precision requirements while maintaining operational reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution simplifies production, enhances operational reliability by preventing unwanted leakage currents, and facilitates effective heat dissipation, thereby ensuring high operational reliability and cost-effectiveness in the motor vehicle auxiliary unit.
Implementation Method 1
a thermally conductive compound is provided between the circuit board body and the partition wall, through which heat generated by the power semiconductors can be dissipated
Data Source
Figure 1~2
AI summary
The invention relates to an electric vehicle auxiliary unit (10) comprising an electric drive motor (12). The drive motor (12) is designed as an electronically commutated canned motor and has a can (18) that liquid-tightly separates a permanent magnet motor rotor (15) from a motor stator (20) having several stator coils (24). The drive motor (12) has a partition (30) and a motor controller (50), wherein the partition (30) is arranged substantially in a transverse plane and liquid-tightly separates the motor controller (50) from the motor rotor (15). The motor controller (50) has a circuit board body (52) which is arranged substantially in a transverse plane and attached to the partition (30). The partition (30) has at least two axial support studs (34, 35) on which the circuit board body (52) is axially supported with its proximal side (53).At least one fastening element (40) is provided by which the circuit board body (52) is held axially on the partition.